tock-mirror/fco2/Types.hs
2007-04-12 16:55:26 +00:00

132 lines
4.4 KiB
Haskell

-- | Type inference and checking.
module Types where
-- FIXME: This module is a mess -- sort it and document the functions.
-- FIXME: These functions should have state-monadic versions.
-- It'd be nice if we could provide an instance of StateMonad for the Parsec state...
import Control.Monad
import qualified AST as A
import ParseState
perhaps :: Maybe a -> (a -> b) -> Maybe b
perhaps m f = m >>= (Just . f)
sameName :: A.Name -> A.Name -> Bool
sameName a b = A.nameName a == A.nameName b
specTypeOfName :: ParseState -> A.Name -> Maybe A.SpecType
specTypeOfName ps n
= (psLookupName ps n) `perhaps` A.ndType
abbrevModeOfName :: ParseState -> A.Name -> Maybe A.AbbrevMode
abbrevModeOfName ps n
= (psLookupName ps n) `perhaps` A.ndAbbrevMode
typeOfName :: ParseState -> A.Name -> Maybe A.Type
typeOfName ps n
= case specTypeOfName ps n of
Just (A.Declaration m t) -> Just t
Just (A.Is m am t v) -> typeOfVariable ps v
Just (A.IsExpr m am t e) -> typeOfExpression ps e
Just (A.IsChannelArray m t (c:_)) -> typeOfVariable ps c `perhaps` A.Array [A.UnknownDimension]
Just (A.Retypes m am t v) -> Just t
Just (A.RetypesExpr m am t e) -> Just t
_ -> Nothing
-- FIXME: This should fail if the subscript is invalid...
subscriptType :: A.Type -> Maybe A.Type
subscriptType (A.Array [_] t) = Just t
subscriptType (A.Array (_:ds) t) = Just $ A.Array ds t
subscriptType _ = Nothing
typeOfVariable :: ParseState -> A.Variable -> Maybe A.Type
typeOfVariable ps (A.Variable m n) = typeOfName ps n
typeOfVariable ps (A.SubscriptedVariable m s v)
= typeOfVariable ps v >>= subscriptType
abbrevModeOfVariable :: ParseState -> A.Variable -> Maybe A.AbbrevMode
abbrevModeOfVariable ps (A.Variable _ n) = abbrevModeOfName ps n
abbrevModeOfVariable ps (A.SubscriptedVariable _ _ v) = abbrevModeOfVariable ps v
dyadicIsBoolean :: A.DyadicOp -> Bool
dyadicIsBoolean A.Eq = True
dyadicIsBoolean A.NotEq = True
dyadicIsBoolean A.Less = True
dyadicIsBoolean A.More = True
dyadicIsBoolean A.LessEq = True
dyadicIsBoolean A.MoreEq = True
dyadicIsBoolean A.After = True
dyadicIsBoolean _ = False
typeOfExpression :: ParseState -> A.Expression -> Maybe A.Type
typeOfExpression ps e
= case e of
A.Monadic m op e -> typeOfExpression ps e
A.Dyadic m op e f ->
if dyadicIsBoolean op then Just A.Bool else typeOfExpression ps e
A.MostPos m t -> Just t
A.MostNeg m t -> Just t
A.SizeType m t -> Just A.Int
A.SizeExpr m t -> Just A.Int
A.Conversion m cm t e -> Just t
A.ExprVariable m v -> typeOfVariable ps v
A.ExprLiteral m l -> typeOfLiteral ps l
A.True m -> Just A.Bool
A.False m -> Just A.Bool
A.FunctionCall m n es ->
case returnTypesOfFunction ps n of
Just [t] -> Just t
_ -> Nothing
A.SubscriptedExpr m s e ->
typeOfExpression ps e >>= subscriptType
A.BytesInExpr m e -> Just A.Int
A.BytesInType m t -> Just A.Int
A.OffsetOf m t n -> Just A.Int
typeOfLiteral :: ParseState -> A.Literal -> Maybe A.Type
typeOfLiteral ps (A.Literal m t lr) = Just t
typeOfLiteral ps (A.SubscriptedLiteral m s l)
= typeOfLiteral ps l >>= subscriptType
returnTypesOfFunction :: ParseState -> A.Name -> Maybe [A.Type]
returnTypesOfFunction ps n
= case specTypeOfName ps n of
Just (A.Function m rs fs vp) -> Just rs
_ -> Nothing
isCaseProtocolType :: ParseState -> A.Type -> Bool
isCaseProtocolType ps (A.Chan (A.UserProtocol pr))
= case specTypeOfName ps pr of
Just (A.ProtocolCase _ _) -> True
_ -> False
isCaseProtocolType ps _ = False
abbrevModeOfSpec :: A.SpecType -> A.AbbrevMode
abbrevModeOfSpec s
= case s of
A.Is _ am _ _ -> am
A.IsExpr _ am _ _ -> am
A.IsChannelArray _ _ _ -> A.Abbrev
A.Retypes _ am _ _ -> am
A.RetypesExpr _ am _ _ -> am
_ -> A.Original
-- | Add an array dimension to a type; if it's already an array it'll just add
-- a new dimension to the existing array.
makeArrayType :: A.Dimension -> A.Type -> A.Type
makeArrayType d (A.Array ds t) = A.Array (d : ds) t
makeArrayType d t = A.Array [d] t
isChannelType :: A.Type -> Bool
isChannelType (A.Array _ t) = isChannelType t
isChannelType (A.Chan _) = True
isChannelType _ = False
stripArrayType :: A.Type -> A.Type
stripArrayType (A.Array _ t) = stripArrayType t
stripArrayType t = t